Expansion valve mechanism for refrigerating systems



Aug. 31, 1937. A. s. LOCKE 2,091,787

EXPANSION VALVE MECHANISM FOR REIFRIGIIRATINGk SYSTEMS Filed Sept. 28, 1935 INVENTQR' y A. 5. Qc/fe Patented Ang.` 1937 UNITED aosissi EXPANsroN VALVE imcnANlsM Fon. BE-

FGERAZHNG Arthur S. Locke,

Philadelpa,

SYSTEMS Pa., assigner to Baldwin-Southwark Garporation, a corporation oi Delaware Application September 2d, i935, Seriai No. @2,591 l d lilla. This invention relates and evaporator are interchanged for heating or cooling purposes, .and relates more particularly 5 to an improved expansion valve mechanism for 'I such a system.

Various expansion valve and trap arrangements have heretofore been proposed for use in refrigerating systems of the type wherein the condenser lo and evaporator functions are interchanged, but the valve or trap devices have certain defects either in expense, `complication of structure or delay in bringing the refrlgerating cycle up to normal.

It is one object of my invention to provide an improved expansion valve 4mechanism operable to control ow of high pressure refrigerant in either direction therethrough with equal degrees oi' eifectiveness and to do so with a device which is 20 relatively simple in structure and mode of cperation.

A further object is to provide an improved dual functioning expansion valve mechanism that is operable with either cycle to prevent how of re- 5 frigerant during the period in which the refrigerant is being pumped up to substantially its normal high pressure. As a result of this improved mode of operation, there is the possibility of accumulating condensed refrigerant at the i expansion valve orlce before opening thereof regardless of the direction of flow therethrough. Hence there is little likelihood of gas flowing through the expansion valve orice during the initial operation of the refrigeration cycle. A further result of my improved mechanism particularly in combination with the condenser and evaporator is that the expansion valve oriilce, in either direction of uid flow therethrough, will be controlled automatically in accordance with D the rate 'of evaporation o1' the liquid refrigerant.'

Other objects and advantages will be more apparent to those skilled in the art from the following description of the accompanying drawing in which:

i' Fig. 1 is a diagrammatic outline of a compressor, a pair of complementary heat exchange elements functioning respectively either as a, condenser or evaporator, and my improved expansion valve mechanism;

Fig. 2 is an enlarged sectional view of the expansion valve mechanism.

In the particular embodiment o1' the invention which'is disclosed herein merely for the purpose of illustrating one specific form among possible others that the invention might take in practice,

generally to a refrigera-- tion system in which the functions of a condenser through the (Uil.l

I have shown in Fig. li a motor-compressor unit i specically of the piston and cylinder type although it will be understood that any other suitable form of compressor may be employed. High pressure refrigerant is discharged from cylinders i thence through a high pressure pipe 3 connected to two reversing valves il and d. With the valves in the position as shown, the -high pressure iluid iiows through a pipe t to one of the heat exchange elements i now functioning as a condenser. The high pressure fluid thence hows expansion valve mechanism generally indicated at t and through the other heat exchange element t now functioning as an evaporator. The element t then communicates through valve t with a suction pipe i@ leading to the intake ci the compressor. When valves l and ii are rotated through 90, discharge pipe t is connected through valve il to heat exchange elements u and suction pipe It is connected through valve t to pipe t, thereby reversing the evaporator and condenser functions of the heat exchange elements. It will be understood that any suitable medium s uch as air or water is cir# culated over the heat exchange elements l and t depending upon the type of heat transfer system that is employed.

The specific expansion valvemechanism comprises a split casing with a diaphragm il interposed therebetween, thereby forming two chambers i2 and i3. Anexpansion orifice I 4 is formed in one wall of chamber i2 while a valve I5, secured to the diaphragm, is slidably received within said orlice and has flutes I6 and Il terminating short oi each other to provide a continuous peripheral portion I8 of suitable axial length depending upon how far it is desired to have the valvemove before permitting flow of refrigerant through the expansion orifice. A spring is interposed between an adjustable plug 2l and a flange 22 of a sleeve 23, the plug being suitably hermetically sealed after adjustment. 'Ihis sleeve is slidably supported upon a cylindrical guide 24 formed integrally with plug 2|, while a, stop ange 25 is adapted for engagement with a shoulder 26 formed on sleeve 23. This arrangement limits inward movement of liange 22 so that it is preierably lust slightly spaced from a collar 21 of the diaphragm when in its neutral position as shown in Fig. 2: A similar Jspring and sleeve arrangement is provided on the other side of the diaphragm and the corresponding parts have the same reference numbers prlmed,`it being noted however that guide 24 is hollow and somewhat larger than guide 24 so as to receive valve l5 and position as indicated in Fig. 1, heat exchangeelements 1 and l function respectively as a condenser and evaporator. Assuming that the compressor is not running and that the pressure throughout the system is equallaed.- then diaphragm Il is in its neutral position and expansion valve I! is in its closed position as shown in Fig. 2. Upon starting of the compressor, pressure will build up in condenser 1 and chamber I2 before the expansion valve I5 opens. Movement in a left hand direction of diaphragm Il under this increasing pressure will be resisted by spring 2l up to some predetermined pressure at which accumulation of condensed liquid refrigerant in chamber I2 will be insured. When such a predetermined pressure has been reached, diaphragm I I will then move to compress spring 20 and open expansion orifice Il. The spring 2l' will be unable to move diaphragm II to the left because of stop flange 25 being in engagementv with shoulder. 26'. The movement of diaphragm II to 30 the left is assisted by reason of chamber Il being subjected to the suction pressure in the low pressure or evaporator side 9 of the system, this communication being established throughra pipe 3l. So long as the rate of evaporation is auch that the suction pressure is maintained within its normal limits, then diaphragm II jected to this suction pressure on its left side will permit the cooperating high pressure in chamber I2 to maintain expansion valve I5 in its open position, that is, so that liquid flows through fiute I1 to pipe 9. However, if the rate of evaporation should decrease so that suction pressure in chamber I3 would increase to some predetermined value, then the forces on the diaphragm will tend to become balanced with the result that valve I5 will move in a right hand direction to either restrict or close of! flow of condenser refrigerant through the expansion orifice. How- -ever, when the rate' of expansion increases so that the suction pressure decreases, then the expansion orifice will again open in a left hand direction.

When the condenser and evaporator functions are interchanged by rotation of valves I and I through 90, then high pressure in heat exchange element 9 (now functioning as a condenser) will be transmitted through pipe il to chamber Il, whereas chamber I2 by being connected to heat exchange element 1 (now functioning as an evaporator) will be subjected to suction pressure. Hence the operation of expansion valve Il will be reversed -to that above described. With this reversed operation, liquid will accumulate inthe bottom of heat exchange element 9 adjacent to the right hand side of expansion orlce I4. The valve I5 will move in a right hand direction to permit flow of liquid refrigerant through flutes It and thence through chamber I2 to heat ex- .m change element 1. In this reverse cycle of operation, the diaphragm will be working against spring 20' and accordingly the action of the expansion valve in response to variations in suction pressure will be controlled in the same manner as previously described for the other cycle by being subi 'spring for of operation, wherein chamber Il was subjected to suction pressure.

From the foregoing disclosure it is seen that I have provided a simple and effective expansion valve mechanism operative in a so-called reverse cycle refrigerating system so as to assist in having the expansion orifice open substantially. only when there is an accumulation of liquid thereby preventing free fiow of gas through the expansion orifice when the compressor is started. In previous expansion valves for reverse cycle refrigeration, if the compressor has been shut down and the system is filled only with refrigerant gas, then an appreciable period of time may be required to build up sufficient condenser pressure for effecting condensation of the refrigerant due to the fact that ,refrigerant gas will immediately start to flow through the orifice, whereas in my improved arrangement there is a definite stoppage of the flow of gas through the expansion orifice until a predetermined high pressure has been reached. It is also seen that the foregoing results are accomplished automatically in response to the direction of fluid flow through the heat exchange elements and that substantially similar pressure conditions operate the expansion valve mechanism in either direction of flow therethrough.

'It will of course be understood that various changes in details of construction and arrangement of parts may be made by'those skilled in the art without departing from the spirit of the invention as set forth in the appended claims.

I claim:

1. In combination, a refrigerating system having high and low pressure sides, lmeans for interchanging said sides, an expansion orifice through which high pressure ows in either one of opposite directions depending upon which one of the sides of the refrigerating system is under high pressure, and means for controlling ow of refrigerant through said orifice in accordance with. a predetermined pressure on the high side.

2. The combination set forth in claim 1 further characterized in that said control means includes a valve element for said orifice,v a diaphragm to which said valve is operatively connected, and means forming a pair of pressure chambers on opposite sides of said diaphragm.

3. The combination set forth in claim 1 further characterized in that said control means includes a valve element for said orifice, a diaphragm to which said valve is operatively connected, means forming a pair of'pressure chambers on opposite sides of said diaphragm, and means whereby said chambers communicate respectively with the opposite sides of the refrigeration system.

4. The combination set forth in claim 1 further characterized in that said control means includes a valve element for said orifice, a diaphragm to which said valve is operatively connected, means forming a pair of pressure chambers on opposite sides of said diaphragm, means whereby said chambers communicate respectively with the opposite sides of the refrigeration system, and a resisting movement of the diaphragm in one direction from a neutral position.

5. 'Ihe combination set forth in claim 1 further characterized in that said control means includes a valve element for said orifice, a diaphragm to which said valve is operatively connected, means forming a pair of pressure chambers on opposite sides of said diaphragm, means with the opposite a-,oeifrsv whereby said chambers communicate respectively sides ot the refrigeration system, a spring for resisting movement of the diaphragm in onedirection from a neutral position, and means for preventing said spring from moving the diaphragm in the opposite direction 'from said neutral position.

6. The combination set forth in claim i'turther i characterized in that said control means includesavalve element for said oriiice.a diaphragm cludes a valve element for said, oriiice, 'a diaphr'agm to which said valve is loperatively connected, bers on opposite sides of said diaphragm. means whereby said chambers communicate respectively with the opposite -sides of the refrigeration sys-v tem. and a. pair oi' springs adapted to resist movement oi the diaphragm in either oi' opposite directions trom a neutral position. v v l 7. The combination set forth in claim 1 further characterized in that said control means into which said valve is--operativ'ely connected.

.means forming a pair oi' pressure chambers on means forming a pair oi' pressure chamopposite sides of said diaphragm. means whereby said chambers communicate respectively with the opposite sides of in one direction from a neutral position, means for preventing said spring from moving the diaphragm in the opposite direction from said-neutral position, and means for preventing said springs from moving said diaphragm in either direction past said neutral position.

8. Expansion apparatus for a refrigerating system having high and low pressure lsides adaptand pressure responsive means for actuating said oi' refrigerant through said` with a predetermined pres- 2`0 valve `tc control ilow oriiice in accordance sure on the high side. ARTHUR S. LOCKE.

the refrigeration system', a spring for resisting movement o! the diaphragm v 

